San Diego DNA vaccine developer Vical will get up to $130 million for licensing the development and commercial rights for its experimental TransVax treatment to Astellas Pharma of Japan, the company said Thursday afternoon.

The deal includes a $25 million upfront payment to Vical, a $10 million payment when a phase 3 clinical trial of the therapy is fully designed and up to $95 million more in future milestone payments.

TransVax prevents the activation of cytomegalovirus, a common herpesvirus that is dormant in most people but can cause illness and even death in those with compromised immune systems.

Vical has mainly tested the vaccine in people who have undergone bone marrow transplants.

“This speaks to the validation of our platform,” said Vijay Samant, president and chief executive officer of Vical. "The acceptance of our data by big pharma really opens up the application of our technology to other targets."

The announcement came after the close of stock markets. In after-hours trading, shares of Vical were up 43 cents, or 10 percent, to $4.73.

Astellas will take over all drug development activity and will sell the vaccine in the United States and other countries once it receives regulatory approval.

In addition to moving forward with a phase 3 trial in bone marrow transplant patients, the companies said they will pursue a phase 2 trial of the vaccine in organ transplant patients.

The agreement was bolstered by positive results from an earlier phase 2 trials of TransVax in bone marrow transplant patients, said Yoshihiko Hatanaka, president and chief executive officer of Astellas.

Vical officials reported the test results Thursday morning at the International Society of DNA Vaccines annual conference being held in San Diego.

For 12 months after their bone marrow transplants, patients who received the vaccine showed significant improvement over a placebo group in all of the study’s key endpoints, including fewer occurrence of the virus in their blood, longer average time to reactivation, fewer reactivation episodes and shorter reactivation periods, said Alain Rolland, Vical’s executive vice president of product development.

TransVax and other vaccines being developed by Vical use specially designed circular pieces of DNA to trigger the production of proteins in the body, prompting the immune system to produce antibodies in response that target specific viruses, bacteria and parasites.

Astellas’ deal with Vical is the third major licensing pact signed by the Japanese company with a San Diego drug developer in the last year and a half.

In February, the European division of Astellas agreed to pay Optimer Pharmaceuticals $68 million up front and another $156 million in milestone payments to sell the San Diego company’s new antibiotic in Europe, Africa, the Middle East and former Soviet Union countries.

In late 2009, Astellas agreed to pay Ambit Biosciences $40 million up front and $350 million in milestone payments to jointly develop drugs known as kinase inhibitors to treat acute myeloid leukemia and other diseases.